Physical conditions on the moon. Our natural satellite is the moon. What are the physical conditions on the surface of the moon?

The lunar surface is lifeless and empty. Its peculiarity is the complete absence of atmospheric effects that are observed on Earth. Night and day come instantly as soon as the rays of the Sun appear.

Due to lack of distribution medium sound waves, complete silence reigns on the surface.

The axis of rotation of the Moon is tilted only 1.5 0 from the normal to the ecliptic, so the Moon does not have any seasons or changes in the seasons. Sunlight is always almost horizontal at the lunar poles, making these areas constantly cold and dark.

The lunar surface changes under the influence of human activity, meteorite bombardment, and irradiation with high-energy particles (X-rays and cosmic rays). These factors do not have a noticeable impact, but over astronomical times they “plow” strongly surface layer- regolith.

When a meteor particle hits the surface of the Moon, a miniature explosion occurs and particles of soil and meteorite matter are scattered in all directions. Most of these particles leave the gravitational field of the Moon.

The range of daily temperature fluctuations is 250 0 C. It ranges from 101 0 to -153 0. But heating and cooling of rocks occurs slowly. Rapid temperature changes occur only during lunar eclipses. It was measured that the temperature varies from 71 to - 79 C per hour.

The temperature of the underlying layers was measured using radio astronomical methods; it turned out to be constant at a depth of 1 m and equal to -50 C at the equator. This means the top layer is a good heat insulator.

Analysis of lunar rocks brought to Earth showed that they were never exposed to water.

The average density of the Moon is 3.3 g/cm 3 .

The period of revolution of the Moon around its axis is equal to the period of its revolution around the Earth, so it is observed from the Earth only on one side. The far side of the Moon was first photographed in 1959.

The light areas of the lunar surface are called continents and occupy 60% of its surface. These are rugged, mountainous areas. The remaining 40% of the surface is sea. These are depressions filled with dark lava and dust. They were named in the 17th century.

The continents are crossed by mountain ranges located along the coasts of the seas. Highest height the lunar mountains reach 9 km.

Most lunar craters are of meteorite origin. There are few volcanic ones, but there are also combined ones. The largest lunar craters have a diameter of up to 100 km.

Bright flares have been observed on the Moon, which may be associated with volcanic eruptions.

The Moon has almost no liquid core, as evidenced by the absence magnetic field. Magnetometers show that the Moon's magnetic field does not exceed 1/10,000 of the Earth's.

Atmosphere:

Although the Moon is surrounded by a vacuum more perfect than the one that can be created in terrestrial laboratory conditions, its atmosphere is vast and of high scientific interest.

During the two-week lunar day, atoms and molecules knocked off the lunar surface into ballistic trajectories by a series of processes are ionized by solar radiation and then driven by electromagnetic effects as plasma.

The position of the Moon in orbit determines the behavior of the atmosphere.

The dimensions of atmospheric phenomena were measured by a series of instruments placed on the lunar surface by the Apollo astronauts. But data analysis was hampered by the fact that the natural lunar atmosphere is so thin that contamination from gases emanating from Apollo significantly affected the results.

The main gases present on the Moon are neon, hydrogen, helium, and argon.

In addition to surface gases, small amounts of dust were found circulating up to several meters above the surface.

The number of atoms and molecules per unit volume of the atmosphere is less than a trillionth of the number of particles contained in a unit volume of the earth's atmosphere at sea level. The Moon's gravity is too weak to hold molecules near the surface.

Any body with a speed greater than 2.4 km/s will escape the gravitational control of the Moon. This speed is a little faster average speed hydrogen molecules at ordinary temperature. Hydrogen dissipation occurs almost instantly. The dissipation of oxygen and nitrogen occurs more slowly, because these molecules are heavier. In astronomically short periods of time, the Moon is capable of losing its entire atmosphere, if it ever had one.

Now the atmosphere is replenished from interplanetary space.

M. Mendillo and D. Bomgardner (Boston University), after analyzing the results of observations of the total lunar eclipse of November 29, 1993, came to the conclusion that the lunar atmosphere is 2 times more extensive (equal to 10 diameters of the Moon) than previously thought.

It is maintained not by impacts of micrometeorites and elementary particles of the solar wind (protons and electrons) on the lunar soil, but by the influence of light and thermal photons from solar radiation on it.

The main components are atoms and ions of sodium and potassium knocked out of the lunar soil. The atmosphere is very rarefied, but sodium atoms are easily excited and radiate strongly, so they are easy to detect. (Nature 5.10.1995).

Origin: According to the prevailing modern theories The Moon was formed together with the Earth from the same planetesimal. Scientists believe that initially the Moon was very close to the Earth, and J. Darwin wrote that the Moon was once in contact with the Earth and the orbital period of the two bodies was about 4 hours. But this assumption seems unlikely. Many believe that the Moon formed at a distance significantly less than half its present one. In this case, tidal waves on Earth would have to reach 1 km.

There are other theories. New evidence has been found for the hypothesis that the Moon was formed from the collision of some body with the Earth.

According to data from the Moon's Clementine satellite, processed at the University of Hawaii

Those (USA), a map of the percentage of iron on the surface of the Moon was compiled. It can vary from 0% in the mountains to 14% at the bottom of the seas. If the Moon had the same mineralogical composition as the Earth, then there would be much more iron. This means that it was unlikely to have formed from the same protoplanetary cloud with the Earth.

Vast areas on the far side of the Moon contain no iron at all, but are covered with anorthosite, a rock rich in aluminum. Pure anorthosite is rare on Earth.

Impact on Earth: Americans R. Bolling and R. Cerveny studied data on

global temperature distribution obtained from satellites between 1797 and 1994. From the data it follows that the Earth is warm when the Moon is full, and cold when the Moon is new. With its light during the full moon, the Moon warms the Earth by 0.02 0 C. Even such temperature changes can affect the Earth's climate. (Astronomy Now, May 1995).

The successful soft landing on the lunar surface of the Luna-9 space station is a new stage in the study of the nature of the Moon, the beginning of direct experiments on its surface.

The Earth - Moon is the only “double planet” of its kind in the solar system. The fundamental problem of the origin of the Moon has been considered by many researchers. The results turned out to be quite contradictory. However, there is no doubt about the qualitative conclusion made by J. Darwin in his classical research tidal history of the Earth-Moon system. J. Darwin believed that tidal friction, caused mainly by shallow seas, should continuously slow down the rotation of the Earth and at the same time, increasing the angular momentum of the Moon, expand its orbit. Consequently, the Earth rotated faster in the past, and the Moon was closer to the Earth. Note that the “secular effect” of tidal friction at shorter distances was significantly greater than now.

The gradual removal of the Moon from the Earth is confirmed by direct observations. It is known that even today the length of the day is increasing. Further, studies of the structure of corals showed that in the early Paleozoic the day was about 20 hours and the number of days in a year was greater.

To solve the problem of the origin of the Moon, it would be necessary to calculate at what distance from the Earth the Moon was at the very beginning of the formation of the solar system. As studies of meteorite (and therefore asteroid) matter show, the solar system formed about 4.5 billion years ago.

However, it is currently still impossible to make a fairly confident calculation of the tidal evolution of the Earth-Moon system. First, it is impossible to say how the gradual accumulation of ocean basins occurred and how tidal friction changed. Secondly, it has now been established that all matter on the Earth plays a significant role in tidal phenomena.

J. Darwin, accepting the maximum possible deviation of the tidal hump from the line between the centers of the Earth and the Moon, found that the Moon should have been in close proximity to the Earth only 57 million years ago, which, of course, has nothing to do with reality. Without mentioning some contradictory results, we point out that based on the totality of a number of studies, including recent calculations by E. L. Ruskol, it can be considered that the Moon in the past moved in an orbit with a lower eccentricity, i.e., more approaching a circular one, with less inclination to the plane of the earth's equator, and the shortest distance of the Moon from the Earth was several radii of the Earth. It is very likely that the Moon was at its smallest distance several billion years ago - at the very beginning of the history of our planet.

These conclusions, due to the uncertainty of the initial data, are more or less qualitative in nature, but they indicate that the Moon was never captured by the Earth, but was formed together with it in a single process of cosmic evolution. Such a process of formation of double and even multiple bodies is a very common phenomenon in space, and our Sun, formed as a result of a small rotational moment as a single body, is a rather rare exception. The role of the Moon in the process of formation of the Earth-Moon system was precisely that even before the final separation of the Earth from the original protoplanetary mass, the Moon accounted for the largest part of the rotational moment. This contributed to the formation of the Earth in the form of a single and fairly stable body. Other planets were in different conditions. For example, Venus, a planet of approximately the same mass as the Earth, but with a completely negligible rotational moment (Venus rotates around its axis with a period of about 250 days and, moreover, in the opposite direction), has always been in a stable state and therefore should not have “acquired” satellite.

The question of the origin of the Moon is also related to its thermal history, which largely determines the physical conditions on the lunar surface. Calculations of the thermal history of the Moon, carried out in detail, mainly in the USSR and the USA,
are rather conditional due to the uncertainty of the initial data. It is usually assumed that the composition of the Earth and the Moon is close to stony meteorites - chondrites, which contain many long-lived radioactive elements (potassium-40, thorium and two isotopes of uranium). With a uniform distribution of radioactive elements within the mass of a planetary body, the energy released during their decay is almost completely absorbed, gradually increasing the temperature of the interior. To calculate, you need to set the most probable values ​​of thermal conductivity, density and specific heat capacity at all distances from the center of the planet and take into account at what heating the complete or partial melting of the substance can occur. Depending on certain prerequisites, different authors found that the Moon throughout its history either remained solid or, on the contrary, was molten up to 0.8 radius, counting from the center.

The central parts of the Moon could heat up to approximately 1300° K (G. Yuri) or up to 2000° K (B. Yu. Levin, S. V. Maeva). Less heating could occur if radioactive elements accumulated predominantly in the surface layers.

However, these calculations still do not resolve the question of whether a more or less significant melting of the Moon’s substance can take place. It seems doubtful whether chondrites are the most characteristic material of the composition of the Moon and planets. IN Lately The primary substance is considered to be carbonaceous chondrites. Further, in addition to the decay of long-lived radioactive elements, there may be other sources of heating, namely ordinary gravitational heating during the rapid compression of the resulting cosmic body. It is also necessary to take into account the release of chemical energy during the formation of complex molecular compounds, which are part of the Moon. The role of short-lived radioactive isotopes, which, according to the latest data, should have played, is still unclear significant role during the formation of asteroidal and, consequently, planetary matter. Finally, in the first epoch of its existence, when the Moon was relatively close to the Earth, the energy of tidal friction must have had a significant influence. Thus, the problem of the thermal history of the Moon cannot be solved purely theoretically. It is necessary to compare a variety of observational material.

The first determinations of lunar temperature based on measurements of infrared radiation were carried out back in 1868 by Lord Ross, and then in more detail, starting in 1927, by E. Pettit and S. Nicholson. On average, the temperature of the subsolar point turned out to be about 390° K, and at the antisolar point it was quite confidently 120° K. The maximum temperature value that had to be measured was 405° K. So, over the time lunar days the amplitude of temperature fluctuations is about 280°. This is one of the most important quantities characterizing conditions on the Moon. With sunrise, the surface temperature rises rapidly, passes through a fairly flat maximum and then relatively slowly reaches a minimum value. It is interesting that sharp jumps in temperature (over 200°) are observed even during total lunar eclipses, which have a relatively short duration. All this means that solar radiation heats only the most superficial layers of the lunar cover, that the thermal conductivity of lunar rocks is negligible and, as calculations show, should be about a thousand times less than the thermal conductivity of typical terrestrial minerals.

It is important to emphasize that the temperature distribution depends on the reflectivity of a given area of ​​the lunar surface. Thus, craters with a higher albedo heat up slightly less than the surrounding area during the day. In general, mountainous areas warm less than darker seas.

Interesting results have recently been obtained using radio methods. For example, V.S. Troitsky measured the intensity of lunar radio emission at wavelengths from 3 to 70 cm. The effective depth of emission of radiation is approximately 20 times greater than the corresponding wavelength. Consequently, a wavelength of 30 cm corresponds to a depth of the emitting layer of 6 m. Therefore, the study of long-wave radio emission allows one to penetrate into the inner layers of the Moon and obtain information about their thermal properties. By combining these data with thermal conductivity measurements, an estimate of the energy flow from the Moon's interior can be made.
Having carried out numerous measurements and using as a standard the radiation of the “artificial Moon” - a disk placed at a distance of several hundred meters from the radiation receiver, V. S. Troitsky found that the average temperature of the Moon quickly increases to a depth of about 6 m, and then increases much more slowly . The total heat flow from the Moon turned out to be approximately the same as from earth's surface, although the mass of matter corresponding to a unit of the surface of the Moon is five times less. The release of heat by the inner regions of the Moon per unit mass, according to V.S. Troitsky, is 4-5 times greater than what is the case for the Earth.

It would seem that this confirms the hypothesis, which in particular adheres to B. Yu. Levin, about a significant melting of lunar matter. However, a case can be made that the Moon should basically be completely solid.

In fact, as is known, data on the thermal history and internal structure of Mars lead to the conclusion that this planet does not have a liquid core of significant size. Mars has a mass 9 times less than Earth's. It has no perceptible magnetic field. The Moon's magnetic field is also very weak, and its mass is 81 times less than the mass of the Earth. Since bodies of lower mass cool faster, it is natural to expect that the Moon is mostly solid.

On the other hand, the shape of the Moon differs significantly from the equilibrium figure of the liquid mass, corresponding to the modern distance from the Earth with a relatively small tidal influence. The elongation of the lunar figure in relation to the Earth is 1 km, while in equilibrium conditions it can be no more than 60 m. It seems to follow from this that the Moon should have almost completely become solid at a relatively short distance from the Earth (corresponding to the orbital period at 6.8 days) and after that continued to maintain its shape.

Note also that despite the higher temperature in the central regions, the Moon could still retain a solid structure (due to significant pressure) and only near the surface could the melting temperature drop enough to allow at least partial melting.

To resolve the issue of the internal structure of the Moon, it is necessary to probe it using seismic methods. For now, we have to limit ourselves to analyzing the relief of the lunar surface and its changes in previous eras.

The most cursory survey of the lunar surface undoubtedly proves that the lunar maria arose as a result of extensive melting, in which the older ring mountains were partially submerged. For example, that part of the vast Rainbow Bay that adjoins the mountainous region is well preserved. The other half of the bay, located on the surface of the Sea of ​​Rains, completely disappeared.

One can quite confidently trace the successive succession of different eras in the formation of the lunar relief. On the surface of the Moon, more ancient ring mountains, melts that formed the lunar seas, relatively recent relief features, craters with central hills, domes, etc. are noticeable. The sequence of development of lunar forms was studied in detail by A. V. Khabakov.

What is the reason for the changes in the relief of the Moon? G. Urey considered the formation of the Mare Mons as the result of an oblique impact of a large asteroid on the Moon, but this unlikely, although possible, event cannot be the main cause. The appearance of lunar meltdowns dates back to a certain era in the evolution of the Moon and, for some reason, was associated only with the hemisphere facing the Earth. Indeed, on the far side of the Moon, seas are almost completely absent. Perhaps the impacts of large meteorite bodies only contributed to the manifestation of local activity.

If we assume that the formation of the lunar relief is due to internal activity, then it should be accompanied by the accompanying release of gases and water vapor, just as it happened and is now happening to a weak extent on Earth. However, the relatively weak gravity of the Moon could not hold the gases near its surface and they quickly evaporated into space.

Theoretical calculations show that at the maximum surface temperature (400° K), hydrogen is retained by the Moon for only about twenty minutes. Oxygen and water vapor, which quickly decompose under the influence of ultraviolet solar radiation, can remain on the lunar surface for about a year and a half. Carbon dioxide persists for several hundred million years, and the heaviest gases - krypton and especially xenon - for almost the entire existence of the Moon. Some heavy gases, such as carbon dioxide, must accumulate if there is even minimal volcanic activity on the Moon. Others - xenon, krypton - could be released during radioactive decay. However, the most thorough studies of the Moon using various methods have not led to the discovery of any gaseous shell. The most sensitive method, based on the observation of lunar occultations of point radio sources, showed that the upper limit of atmospheric pressure on the Moon should be 10,000 billion times less than on Earth at sea level, i.e., the Moon is practically completely devoid of an atmosphere.

The release of gases from the central hill of the Alfons crater was observed by N.A. Kozyrev on November 3, 1958 and October 23, 1959. Surprisingly, it turned out to be not water vapor or any oxygen compound, but molecular carbon Cr, which is usually part of heads comets, but is never released on Earth. The absence of any gases that could remain near the lunar surface for a sufficient time can be explained by the influence of the solar wind, which blows the slightest traces of the lunar atmosphere into interplanetary space.

The topographic properties of the Moon deserve special attention. As is known, ring formations predominate on the Moon. These are extensive ring mountains with a diameter of over 200 km (for example, Clavius), ordinary craters (often with central mountains) several tens of kilometers in size, and small holes only meters across.

Even lunar seas, thousands of kilometers in size, if they are isolated and do not overlap with other similar formations. have very regular circular outlines, for example the Sea of ​​Crises and a number of others. In addition, on the Moon there are polygonal shapes, hexagonal shafts located on more or less flat ground. They were first noted by the famous selenologist P. Puizet and are especially clearly represented around North Pole. The same researcher discovered “domes” in the Sea of ​​Tranquility - small round bulges. Subsequently, many domes were discovered in other places on the Moon, mainly on the surface of the seas, where they are easier to notice. At the top of the dome there is usually an opening like a volcanic vent. In addition, inside the seas and large craters there are many grooves, usually located along the ridges and resembling cracks. The most pronounced system of such cracks is clearly visible in the center of the lunar disk near the Triesnecker crater. A sharp groove is also noticeable there. It changes direction as it passes through the small Hyginus crater. These grooves in some areas of the Moon form entire systems of parallel
line lines associated with the predominant direction of craters and their ridges. Finally, a characteristic feature of the Moon is radial systems of light rays diverging from individual craters with central hills. They stretch over distances (for example, from the Tycho crater) of thousands of kilometers and pass, without changing direction, through mountainous and lowland areas.

When examining the lunar topography in detail, attention is drawn to the undoubted changes that took place on the Moon over long periods. Very old ring mountains stand out, the ramparts of which have almost disappeared, as if plunging into the ground. Such, for example, is the relict circus of Stages with a diameter of 60 km. Relative analysis of various details on the Moon and a number of terrestrial minerals - granites, basalts, sandstones, as well as various conglomerates, has established a sharp difference between lunar rocks and terrestrial ones. It turned out that lunar rocks are characterized by a small range of colors and reflectivity, while terrestrial minerals, especially in dry mountain deserts, in the absence of dust cover, are distinguished by a wide variety of colors (it is enough to point out the wonderfully colored mountain valley leading from Kenya along the Nile to the Red Sea).

Laboratory experiments suggest that the extreme homogeneity of the lunar surface can be explained by exposure of some minerals to high-frequency radiation. For example, B. Gapke found that minerals rich in weakly oxidized metals - iron, copper, etc., darken quite quickly when irradiated with protons with an energy of about 5 keV, which is caused by the formation of free metal ions near the surface.

Another amazing feature of the lunar surface layer that reflects solar rays is the nature of the reflection indicatrix*. When illuminating the lunar surface, most of the light is reflected in the direction opposite to the incident ray (Recall that an ideal matte surface reflects light in all directions in proportion to the cosine of the angle of incidence.) With this law of reflection, each element of the lunar surface appears especially bright when the incident ray coincides with the direction reflected, i.e. during the full moon. The brightness of a surface element is almost independent of its inclination to the observer's line of sight. As a result, the entire lunar disk appears almost equally bright both in the center and at the edges, which creates the impression of some kind of flat plate rather than a spherical body. As the phase angle decreases, i.e., as the moment of full moon approaches, the brightness of the Moon quickly increases and passes through a sharp maximum.

A detailed examination of these features showed that the surface of the Moon on a scale comparable to the length of light waves should be distinguished by a complex branched structure.
structure such that when illuminated, one element can obscure another. The least effect is obtained, obviously, when the incident beam coincides with the reflected one. On the contrary, the surface of our neighboring Mars, the only planet on which some form of life is assumed, is characterized by complete smoothness, almost coinciding with the smoothness of completely matte surfaces. Thus, a seemingly paradoxical situation is created. The uninhabited Moon is characterized by a surface microstructure that imitates vegetation, and Mars, where there is an atmosphere and some signs of water vapor, turns out to be simply a sandy desert. Similar features in the microstructure are obtained when considering the polarization properties of the lunar surface. It is interesting that even the highest degree of polarization for the entire lunar disk does not exceed 8% (at a phase angle of 90°) and only for the seas it rises to 20%. Comparison with terrestrial matter shows that the observed polarization features are achieved with a branched or honeycomb-like surface structure.

The reason for such structural features of the lunar surface lies in long-term (billions of years!) various cosmic influences. The Moon experiences constant impacts from micrometeorites, the number of which rapidly increases with decreasing mass. They destroy its surface layer. In addition, the Moon is exposed to solar wind, which consists primarily of protons - positively charged hydrogen nuclei moving at speeds of thousands of kilometers per second. Further, as can be judged by the substance of meteorites traveling independently in interplanetary space for hundreds of millions of years, primary cosmic rays cause a certain erosion of the lunar surface. Another reason for erosion is sudden temperature changes, reaching almost 300° during the lunar day, to which the Moon has been exposed at least 50 billion times during its existence.

Irradiation by cosmic rays and solar wind should lead to the accumulation of a noticeable positive charge in the material of the lunar surface. Previously, J. Granger estimated it at 5 V, but now, after calculations by S. Singer, the charge value is accepted as even 20-25 V. The presence of a charge can reduce the thermal conductivity of the outer layer of the Moon.

The optical features of the lunar surface appear only on a scale of thousandths of a millimeter, since the size of the reflective grains of the surface layer of the Moon is on average about 5 microns. In the radio range of centimeter and meter waves, the reflection conditions turn out to be completely different. As the wavelength increases, the reflective properties of the lunar surface approach those of a specularly reflecting sphere. A detailed survey of the lunar surface using radar, which began in 1946, was carried out at various observatories, including in Serpukhov near Moscow at the Okskaya station of the USSR Lebedev Physical Institute. It has been shown that at a wavelength of about 10 cm approximately 50%
The flow of radio waves is reflected from the central part of the Moon (size 0.1 of its radius), and the rest of the energy is dissipated approximately according to Lambert’s law. As the wavelength increases, this diffuse component gradually decreases, and the Moon increasingly acquires the properties of an ideal reflector. Thus, it is now possible to judge the size of the irregularities of the lunar surface, which turned out to be in complete agreement with the images transmitted by the Luna-9 automatic station. In addition, based on reflectivity measurements averaging 0.06, the dielectric constant value (approximately 2.72) is consistent with dry sandy soils on Earth.

Let us make a few comments about the luminescence detected near the craters Tycho, Aristarchus and in some other areas of the Moon. Some lunar rocks, when irradiated with solar ultraviolet radiation, gamma rays and high-energy protons, re-emit energy in the visible spectrum. The possibility of such a phenomenon was first pointed out by F. Link in 1946. Ten years later, J. Dubois and at the same time N.A. Kozyrev gave a method of quantitative determination based on measuring the contours of individual lines of the solar spectrum, which, when luminescent glow is applied to them, become less deep. Luminescence is concentrated only in individual emission bands: 390, 420, 430, 440 mm, and their brightness compared to the reflected solar spectrum, according to Dubois, increases by 10-20%. According to M.I. Mirtova, in the luminescence region of the Aristarchus crater there is a band of 450-550 mm. These phenomena indicate that complex minerals containing elements with high atomic weights are found on the surface of the Moon. On Earth, the mineral scheelite (CaWCU), an oxidized compound of calcium and tungsten, luminesces at the same emission frequency.

The Moon, as can be seen from the features of its relief, has gone through a long and complex evolution. However, even now she is not a dead body, subject only to external influences. On the contrary, changes occur in certain parts of the Moon, although quite rare, but still noticeable. It is enough to point out the disappearance in 1866 of the Linnaeus crater with a diameter of 10 km, located in the middle part of the Mare Serenity. Instead, there was only a deep hole with a diameter of about 2 km, and the ridges of the former crater, apparently filled with a mass of molten substance, are now barely visible. In 1891, some changes in the degree of whitishness were noticed there during a total lunar eclipse.

Smaller changes are occurring elsewhere as well. Thus, some turbidity had long been suspected in the inner part of the Alphonse crater, and then gases were spectroscopically discovered there. Quite mysterious events apparently take place at the bottom of the Plato Circus, located at the northern tip of the huge Sea of ​​​​Simmons. It is assumed that the light stripes visible there, as well as the structure of the relief, change somewhat. A.V. Markov and other observers noted changes in color and reflectivity there. The reason for this is not yet known.

Some observers also noted a change in the reflectivity of the radial zones of the eastern rim of the Aristarchus crater.
There is still much that is unclear in the problem of the origin and evolution of the lunar relief, as well as in the observed properties of the lunar surface. However, over the past decade, in addition to ground-based telescopic research, experiments have begun to be carried out near the Moon and on its surface. Flights of Soviet lunar explorers and American spacecraft make it possible to clarify modern ideas about the Moon. These experiments are also invaluable for understanding our Earth and other planets of the solar system.

In 1609, after the invention of the telescope, humanity was able to examine its space satellite in detail for the first time. Since then, the Moon has been the most studied cosmic body, as well as the first one that man managed to visit.

The first thing we have to figure out is what our satellite is? The answer is unexpected: although the Moon is considered a satellite, technically it is the same full-fledged planet as the Earth. It has large dimensions - 3476 kilometers across at the equator - and a mass of 7.347 × 10 22 kilograms; The Moon is only slightly inferior to the smallest planet in the Solar System. All this makes it a full participant in the Moon-Earth gravitational system.

Another such tandem is known in the Solar System, and Charon. Although the entire mass of our satellite is a little more than a hundredth of the mass of the Earth, the Moon does not orbit the Earth itself - they have a common center of mass. And the proximity of the satellite to us gives rise to another interesting effect, tidal locking. Because of it, the Moon always faces the same side towards the Earth.

Moreover, from the inside, the Moon is structured like a full-fledged planet - it has a crust, a mantle and even a core, and in the distant past there were volcanoes on it. However, nothing remains of the ancient landscapes - over the course of four and a half billion years of the Moon’s history, millions of tons of meteorites and asteroids fell on it, furrowing it, leaving craters. Some of the impacts were so strong that they tore through its crust all the way to its mantle. The pits from such collisions formed lunar maria, dark spots on the Moon that are easily visible from. Moreover, they are present exclusively on the visible side. Why? We will talk about this further.

Among cosmic bodies, the Moon influences the Earth the most - except, perhaps, the Sun. Lunar tides, which regularly raise water levels in the world's oceans, are the most obvious, but not the most powerful, impact of the satellite. Thus, gradually moving away from the Earth, the Moon slows down the rotation of the planet - a solar day has grown from the original 5 to the modern 24 hours. The satellite also serves as a natural barrier against hundreds of meteorites and asteroids, intercepting them as they approach the Earth.

And without a doubt, the Moon is a tasty object for astronomers: both amateurs and professionals. Although the distance to the Moon has been measured to within a meter using laser technology, and soil samples from it have been brought back to Earth many times, there is still room for discovery. For example, scientists are hunting for lunar anomalies- mysterious flashes and lights on the surface of the Moon, not all of which have an explanation. It turns out that our satellite hides much more than is visible on the surface - let's understand the secrets of the Moon together!

Topographic map of the Moon

Characteristics of the Moon

Scientific study of the Moon today is more than 2200 years old. The motion of a satellite in the Earth's sky, its phases and distance from it to the Earth were described in detail by the ancient Greeks - and the internal structure of the Moon and its history are studied to this day by spacecraft. Nevertheless, centuries of work by philosophers, and then physicists and mathematicians, have provided very accurate data about how our Moon looks and moves, and why it is the way it is. All information about the satellite can be divided into several categories that flow from each other.

Orbital characteristics of the Moon

How does the Moon move around the Earth? If our planet were stationary, the satellite would rotate in an almost perfect circle, from time to time slightly approaching and moving away from the planet. But the Earth itself is around the Sun - the Moon has to constantly “catch up” with the planet. And our Earth is not the only body with which our satellite interacts. The Sun, located 390 times farther than the Earth from the Moon, is 333 thousand times more massive than the Earth. And even taking into account the inverse square law, according to which the intensity of any energy source drops sharply with distance, the Sun attracts the Moon 2.2 times stronger than the Earth!

Therefore, the final trajectory of our satellite’s motion resembles a spiral, and a complex one at that. The axis of the lunar orbit fluctuates, the Moon itself periodically approaches and moves away, and on a global scale it even flies away from the Earth. These same fluctuations lead to the fact that the visible side of the Moon is not the same hemisphere of the satellite, but its different parts, which alternately turn towards the Earth due to the “swaying” of the satellite in orbit. These movements of the Moon in longitude and latitude are called librations, and allow us to look beyond the far side of our satellite long before the first flyby by spacecraft. From east to west, the Moon rotates 7.5 degrees, and from north to south - 6.5. Therefore, both poles of the Moon can be easily seen from Earth.

The specific orbital characteristics of the Moon are useful not only to astronomers and cosmonauts - for example, photographers especially appreciate the supermoon: the phase of the Moon in which it reaches its maximum size. This is a full moon during which the Moon is at perigee. Here are the main parameters of our satellite:

• The Moon's orbit is elliptical, its deviation from a perfect circle is about 0.049. Taking into account orbital fluctuations, the minimum distance of the satellite to the Earth (perigee) is 362 thousand kilometers, and the maximum (apogee) is 405 thousand kilometers.
• The common center of mass of the Earth and the Moon is located 4.5 thousand kilometers from the center of the Earth.
• Sidereal month - complete walkthrough The moon's orbit takes 27.3 days. However for full turn around the Earth and the change of lunar phases requires 2.2 days more - after all, during the time that the Moon moves in its orbit, the Earth flies a thirteenth part of its own orbit around the Sun!
• The Moon is tidally locked into the Earth - it rotates on its axis at the same speed as around the Earth. Because of this, the Moon is constantly turned to the Earth with the same side. This condition is typical for satellites that are very close to the planet.

• Night and day on the Moon are very long - half the length of an earthly month.
• During those periods when the Moon comes out from behind globe, it is visible in the sky - the shadow of our planet gradually slides off the satellite, allowing the Sun to illuminate it, and then covers it back. Changes in the illumination of the Moon, visible from the Earth, are called ee. During the new moon, the satellite is not visible in the sky; during the young moon phase, its thin crescent appears, resembling the curl of the letter “P”; in the first quarter, the Moon is exactly half illuminated, and during the full moon it is most noticeable. Further phases - the second quarter and the old moon - occur in the reverse order.

Interesting fact: since moon month shorter than the calendar, sometimes there can be two full moons in one month - the second is called a “blue moon”. It is as bright as an ordinary light - it illuminates the Earth by 0.25 lux (for example, ordinary lighting inside a house is 50 lux). The Earth itself illuminates the Moon 64 times stronger - as much as 16 lux. Of course, all the light is not our own, but reflected sunlight.

• The Moon's orbit is inclined to the Earth's orbital plane and regularly crosses it. The satellite's inclination is constantly changing, varying between 4.5° and 5.3°. It takes more than 18 years for the Moon to change its inclination.
• The Moon moves around the Earth at a speed of 1.02 km/s. This is much less than the speed of the Earth around the Sun - 29.7 km/s. The maximum speed of the spacecraft achieved by the Helios-B solar probe was 66 kilometers per second.

Physical parameters of the Moon and its composition

It took people a long time to understand how big the Moon is and what it consists of. Only in 1753, the scientist R. Bošković was able to prove that the Moon does not have a significant atmosphere, as well as liquid seas - when covered by the Moon, the stars disappear instantly, when their presence would make it possible to observe their gradual “attenuation”. It took another 200 years for the Soviet station Luna 13 to measure the mechanical properties of the lunar surface in 1966. And nothing was known at all about the far side of the Moon until 1959, when the Luna-3 apparatus was able to take its first photographs.

The Apollo 11 spacecraft crew returned the first samples to the surface in 1969. They also became the first people to visit the Moon - until 1972, 6 ships landed on it and 12 astronauts landed. The reliability of these flights was often doubted - however, many of the critics' points were based on their ignorance of space affairs. The American flag, which, according to conspiracy theorists, “could not have flown in the airless space of the Moon,” is in fact solid and static - it was specially reinforced with solid threads. This was done specifically in order to take beautiful pictures - a sagging canvas is not so spectacular.

Many distortions of colors and relief shapes in the reflections on the helmets of the spacesuits in which counterfeits were sought were due to gold plating on the glass, which protected against ultraviolet. Soviet cosmonauts who watched the live broadcast of the astronaut landing also confirmed the authenticity of what was happening. And who can deceive an expert in his field?

And complete geological and topographic maps of our satellite are being compiled to this day. In 2009, the Lunar Reconnaissance Orbiter (LRO) space station not only delivered the most detailed images of the Moon in history, but also proved the presence of large amounts of frozen water on it. He also put an end to the debate about whether people were on the Moon by filming traces of the activities of the Apollo team from low lunar orbit. The device was equipped with equipment from several countries, including Russia.

Since new space states like China and private companies are joining the lunar exploration, new data is arriving every day. We have collected the main parameters of our satellite:

• The surface area of ​​the Moon occupies 37.9x10 6 square kilometers - about 0.07% of the total area of ​​the Earth. Incredibly, this is only 20% greater than the area of ​​all human-inhabited areas on our planet!
• The average density of the Moon is 3.4 g/cm 3 . It is 40% less than the density of the Earth - primarily due to the fact that the satellite is devoid of many heavy elements like iron, which our planet is rich in. In addition, 2% of the Moon's mass is regolith - small crumbs of rock created by cosmic erosion and meteorite impacts, the density of which is lower than normal rock. Its thickness in some places reaches tens of meters!
• Everyone knows that the Moon is much smaller than the Earth, which affects its gravity. Acceleration free fall it is 1.63 m/s 2 - only 16.5 percent of the total gravitational force of the Earth. The astronauts' jumps on the Moon were very high, even though their spacesuits weighed 35.4 kilograms - almost like knight's armor! At the same time, they were still holding back: a fall in a vacuum was quite dangerous. Below is a video of the astronaut jumping from the live broadcast.

• Lunar maria cover about 17% of the entire Moon - mainly its visible side, which is covered by almost a third. They are traces of impacts from particularly heavy meteorites, which literally tore the crust off the satellite. In these places, only a thin, half-kilometer layer of solidified lava—basalt—separates the surface from the lunar mantle. Because the concentration of solids increases closer to the center of any large cosmic body, there is more metal in the lunar maria than anywhere else on the Moon.
• The main form of relief of the Moon is craters and other derivatives from impacts and shock waves from steroids. Huge lunar mountains and circuses were built and changed the structure of the surface of the Moon beyond recognition. Their role was especially strong at the beginning of the history of the Moon, when it was still liquid - the falls raised whole waves of molten stone. This also caused the formation of lunar seas: the side facing the Earth was hotter due to the concentration of heavy substances in it, which is why asteroids affected it more strongly than the cool back side. The reason for this uneven distribution of matter was the gravity of the Earth, which was especially strong at the beginning of the Moon’s history, when it was closer.

• In addition to craters, mountains and seas, there are caves and cracks in the moon - surviving witnesses of the times when the bowels of the Moon were as hot as , and volcanoes were active on it. These caves often contain water ice, like the craters at the poles, which is why they are often considered as sites for future lunar bases.
• The real color of the Moon's surface is very dark, closer to black. All over the Moon there are a variety of colors - from turquoise blue to almost orange. The light gray tint of the Moon from the Earth and in the photographs is due to the high illumination of the Moon by the Sun. Due to its dark color, the surface of the satellite reflects only 12% of all rays falling from our star. If the Moon were brighter, during full moons it would be as bright as day.

How was the Moon formed?

The study of lunar minerals and its history is one of the most difficult disciplines for scientists. The surface of the Moon is open to cosmic rays, and there is nothing to retain heat at the surface - therefore, the satellite heats up to 105 ° C during the day, and cools down to –150 ° C at night. The two-week duration of day and night increases the effect on the surface - and as a result, the minerals of the Moon change beyond recognition with time. However, we managed to find out something.

Today it is believed that the Moon is the product of a collision between a large embryonic planet, Theia, and the Earth, which occurred billions of years ago when our planet was completely molten. Part of the planet that collided with us (and it was the size of ) was absorbed - but its core, along with part of the surface matter of the Earth, was thrown into orbit by inertia, where it remained in the form of the Moon.

This is proven by the deficiency of iron and other metals on the Moon, already mentioned above - by the time Theia tore out a piece of earthly matter, most of the heavy elements of our planet were drawn by gravity inward, to the core. This collision affected the further development of the Earth - it began to rotate faster, and its axis of rotation tilted, which made the change of seasons possible.

Then the Moon developed like an ordinary planet - it formed an iron core, mantle, crust, lithospheric plates and even its own atmosphere. However, the low mass and composition poor in heavy elements led to the fact that the interior of our satellite quickly cooled, and the atmosphere evaporated from the high temperature and lack of a magnetic field. However, some processes inside still occur - due to movements in the lithosphere of the Moon, moonquakes sometimes occur. They represent one of the main dangers for future colonizers of the Moon: their scale reaches 5.5 points on the Richter scale, and they last much longer than those on Earth - there is no ocean capable of absorbing the impulse of the movement of the Earth’s interior.

Basic chemical elements on the Moon - these are silicon, aluminum, calcium and magnesium. The minerals that form these elements are similar to those on Earth and are even found on our planet. However, the main difference between the minerals of the Moon is the absence of exposure to water and oxygen produced by living beings, a high proportion of meteorite impurities and traces of the effects of cosmic radiation. The Earth's ozone layer was formed quite a long time ago, and the atmosphere burns most of the mass of falling meteorites, allowing water and gases to slowly but surely change the appearance of our planet.

Future of the Moon

The Moon is the first cosmic body after Mars that claims priority for human colonization. In a sense, the Moon has already been mastered - the USSR and the USA left state regalia on the satellite, and orbital radio telescopes are hiding behind the far side of the Moon from the Earth, a generator of a lot of interference on the air. However, what does the future hold for our satellite?

The main process, which has already been mentioned more than once in the article, is the moving away of the Moon due to tidal acceleration. It happens quite slowly - the satellite moves away no more than 0.5 centimeters per year. However, something completely different is important here. Moving away from the Earth, the Moon slows down its rotation. Sooner or later, a moment may come when a day on Earth will last as long as a lunar month - 29–30 days.

However, the removal of the Moon will have its limit. After reaching it, the Moon will begin to approach the Earth in turns - and much faster than it was moving away. However, it will not be possible to completely crash into it. 12–20 thousand kilometers from the Earth, its Roche lobe begins - the gravitational limit at which a satellite of a planet can maintain a solid shape. Therefore, the Moon will be torn into millions of small fragments as it approaches. Some of them will fall to Earth, causing a bombardment thousands of times more powerful than nuclear, and the rest will form a ring around the planet like . However, it will not be so bright - the rings of gas giants consist of ice, which is many times brighter than the dark rocks of the Moon - they will not always be visible in the sky. The ring of the Earth will create a problem for astronomers of the future - if, of course, by that time there is anyone left on the planet.

Colonization of the Moon

However, all this will happen in billions of years. Until then, humanity views the Moon as the first potential object for space colonization. However, what exactly is meant by “lunar exploration”? Now we will look at the immediate prospects together.

Many people think of space colonization as similar to New Age colonization of Earth - finding valuable resources, extracting them, and then bringing them back home. However, this does not apply to space - in the next couple of hundred years, delivering a kilogram of gold even from the nearest asteroid will cost more than extracting it from the most complex and dangerous mines. Also, the Moon is unlikely to act as a “dacha sector of the Earth” in the near future - although there are large deposits of valuable resources there, it will be difficult to grow food there.

But our satellite may well become a base for further space exploration in promising directions - for example, Mars. The main problem of astronautics today is restrictions on the weight of spacecraft. To launch, you have to build monstrous structures that require tons of fuel - after all, you need to overcome not only the gravity of the Earth, but also the atmosphere! And if this is an interplanetary ship, then it also needs to be refueled. This seriously constrains designers, forcing them to choose economy over functionality.

The moon is much better suited as a launch pad for spaceships. The lack of an atmosphere and low speed to overcome the Moon's gravity - 2.38 km/s versus 11.2 km/s on Earth - make launches much easier. And the satellite's mineral deposits make it possible to save on the weight of fuel - a stone around the neck of astronautics, which occupies a significant proportion of the mass of any apparatus. If the production of rocket fuel were developed on the Moon, it would be possible to launch large and complex spacecraft assembled from parts delivered from Earth. And assembly on the Moon will be much easier than in low-Earth orbit - and much more reliable.

The technologies existing today make it possible, if not completely, then partially to implement this project. However, any steps in this direction require risk. The investment of huge amounts of money will require research for the necessary minerals, as well as the development, delivery and testing of modules for future lunar bases. And the estimated cost of launching even the initial elements alone can ruin an entire superpower!

Therefore, the colonization of the Moon is not so much the work of scientists and engineers, but of the people of the whole world to achieve such valuable unity. For in the unity of humanity lies the true strength of the Earth.

Almost devoid of atmosphere. If we assume that the Moon had an atmosphere in the past, then it is easy to understand why it does not exist now. The fact is that relatively small (by mass) celestial bodies (like the Moon) cannot retain an atmosphere for a long time. Already at a speed of 2.38 km/s (the second escape velocity for the Moon), gas molecules are able to leave the Moon.

There is no water on the Moon either. The evaporation of water would form a gaseous shell around the Moon, which would quickly dissipate.

In the sky of the Moon the same ones are visible as in the sky of the Earth. Due to the lack of atmosphere, bright stars and planets are visible on the Moon during the day. Therefore, astronauts can navigate on the Moon by the stars both day and night. Orientation by stars acquires on the Moon special meaning, since a magnetic compass is useless there. (The moon does not have a magnetic field like Earth's.)

And Venus can be observed from the Moon even in close proximity to the Sun. The spectacular decoration of the Moon's sky is ours. The Earth's disk is approximately 3.5 times larger than the solar disk.

During the lunar day, which lasts about two Earth weeks, the surface of the Moon becomes very hot and then cools at night (the night on the Moon also lasts almost two Earth weeks). The absence of an atmosphere on the Moon leads to sharp temperature fluctuations during the lunar day. In the area of ​​the “subsolar” point, i.e. where it is at its zenith during the day, the temperature exceeds 400 K (+130 ° C). On opposite side Near the “anti-solar” point of the Moon, the surface of the Moon cools to almost 100 K (-170°C). This means that over the course of one lunar day (29.5 Earth days) the temperature changes by 300 K. Sharp temperature fluctuations that occur on the Moon apply only to its surface. Already at a depth of several tens of centimeters, the temperature practically does not change during the lunar day. This is explained by the poor thermal conductivity of the lunar soil, which does not have time to warm up during the day or cool down at night.

You know that the Moon is now facing the Earth with one side. It wasn't always like this. Billions of years ago, the Moon was closer to the Earth than it is now, and the periods of rotation of the Earth and the Moon's orbit around it were only a few hours. Nature of the Moon very interesting. At the current stage of the evolution of the Earth-Moon system, the period of rotation of the Moon coincided with the period of its revolution. This led to two important consequences. Firstly, the duration of a solar day on the Moon is equal to the synodic month (day and night on the Moon last almost two Earth weeks). Secondly, the Moon always faces the Earth with one hemisphere (we always see the same side of the Moon from the Earth).

Surface of the Moon

Even with the naked eye, vast dark areas (seas) and light areas (continents) are visible on the Moon. They can be examined in more detail through telescopes. Despite the fact that there is not a drop of water in the lunar seas, the old naming system, proposed back in the 17th century, has been preserved in science. Unlike the seas (relatively flat areas of the lunar surface covered with dark matter), the continents are mountainous areas.

On the side of the Moon facing the Earth, the continents occupy about 70%, and the seas - 30% of the territory of the lunar hemisphere visible from the Earth.

A characteristic feature of the lunar relief is ring structures (craters). On the visible side alone, there are approximately 300,000 craters with a diameter of more than 1 km. Among them there are those whose diameters exceed 200 km. Most large lunar craters have a flat bottom, with a hill rising in the center.

Many lunar seas are bordered by long mountain ranges. The ranges are called earthly mountain ranges (Caucasus, Alps, Pyrenees, etc.).

On a full moon, through a small telescope (prism binoculars), the Ocean of Storms, the Sea of ​​Rains, the Sea of ​​Clarity, as well as craters (Tycho, Copernicus, Kepler), from which extended ray systems radiate, are clearly visible. When the Moon is in other phases, then near the boundary of the illuminated and unlit parts of the lunar surface (this boundary is called the terminator), the craters stand out especially prominently.

In contrast to several centuries of telescopic research on the visible side of the Moon, the study of its far side began when, for the first time in the history of science, the far side of the Moon was photographed by the automatic station “Luna - 3” on October 7, 1959. About 6 years later (July 1965) Our other automatic interplanetary station (AMS) “Zond-3”, launched into a heliocentric orbit, transmitted new photographs. At the same time, it was possible to photograph almost all areas of the far side of the Moon that were not in the field of view of the Luna 3 phototelevision devices. The resulting images made it possible to compile maps and atlases of the far side of the Moon, lunar globes and complete maps covering almost the entire surface of the Moon.

The lunar hemisphere, invisible from Earth, is dominated by continents. The average diameter of a large sea – the Moscow Sea – reaches 460 km. Sea-like round or oval formations have been discovered, occupying an intermediate position between the lunar maria and the largest craters. There are many craters on the far side of the Moon (the largest are named after prominent scientists - Lomonosov, Giordano Bruno, Tsiolkovsky, Joliot Curie, etc.). Craters often form long chains stretching for hundreds of kilometers.

Most small and medium-sized lunar craters were formed as a result of the impact of meteorites, which, upon reaching the surface of the Moon, have such kinetic energy that an explosion occurs upon impact. The meteorite is destroyed, crushed; lunar soil scatters in different directions from the explosion site. This is how primary craters are formed. The more of them there are in a given area of ​​the lunar surface, the older the age of this area. Large rocks ejected during the formation of primary craters can, falling onto the surface of the Moon, create secondary craters. It is possible that such secondary craters make up ray systems, which are clearly visible at some large young craters during the full moon. The formation of large craters is probably associated with violent volcanic activity, characteristic of the distant past of the Moon.

The moon is rich in the power of suggestion,
There is always a mystery around her.
She echoes us: “Life is a reflection,
But this ghost is breathing for a reason."
With its damage, two-week death
And with a new sovereign radiance
She talks about sadness that is not aimless,
That light awaits us after we die.
K. Balmont

Lesson 13

Subject: Nature of the Moon.

Target: Introduce students to the nearest cosmic body - the Moon. Physical conditions on the Moon. Relief, rocks, internal structure. Study of the Moon and its meaning. Tidal theory. Rocha zone.

Tasks
1. Educational: continue to form ideas about the natural satellite of the Earth; interest students in observing the surface of the Moon through a telescope; introduce the concepts: “seas” and “continents” of the Moon, craters, lunar regolith, the far side of the Moon; give an idea of ​​tidal action and the Roche zone.
2. Educating: justify the conclusion that the Moon, which represents heavenly body, the nature of which has many similarities with the nature of the Earth, cannot exert the supernatural influence often attributed to it on people. Compare ideas about the Moon that existed before telescopic observations with those obtained as a result of space research, and draw a conclusion about the knowability of the world (data about the far side of the Moon, lunar soil, etc.). Instill pride in students Russian science(the first in the history of astronautics were carried out: a flight to the Moon, photographing the far side of the Moon, a soft landing on the Moon, exploration of the Moon using lunar rovers, etc.). To promote the aesthetic education of students by introducing them to the beauty of the lunar landscape, the sky of the Moon, etc.
3. Developmental: teach to highlight the main thing when analyzing the nature of celestial bodies ( general characteristics, atmospheric features, temperature conditions, surface, etc.).

Know:
1st level (standard)- physical conditions on the Moon, characteristics surfaces.
2nd level- physical conditions on the Moon, characteristic features of the surface, rock composition, the concept of the Roche Zone, the internal structure of the Moon, the significance of tidal action.
Be able to:
1st level (standard)- find the size of an object at a distance and its visibility.
2nd level- find the size of an object at a distance and its visibility, determine whether it falls into the Roche Zone (approximately). Find eclipses at any time using "Red Shift 5.1".

Equipment: Globe of the Moon, maps of the Moon, photographs, transparencies. Tables: planetary satellites, Moon, space flights to the moon. Film “Astronomy”, part 1, fr.6 “Moon”, “Study of the Moon using cosmonautics methods”, filmstrip “The Moon is a satellite of the Earth” or “Surface of the Moon”, “Nature, evolution and origin of the Moon”. CD- "Red Shift 5.1" Excursions = Map of the Moon, Video Gallery = Solar System (Formation of the Moon, Ride the Lunar Rover, Lunar Rover Rover, Landing on the Moon, Takeoff from the Moon, Surface of the Moon): Photo Gallery - Moon. Photographs and illustrations of astronomical objects from the multimedia disc “Multimedia Library for Astronomy”.

Interdisciplinary connections: natural history (preliminary information about the Moon), physics (mass and density of bodies, acceleration of gravity), geography (seas and continents of the Earth), social science (knowability of the world).

During the classes:

1. Results test work(practical, etc., what was asked) (5 min).
2. Student survey(15 minutes)

III. New material(15 minutes)
Zona Rocha
Edward Albert ROSH(1820-1883, France) theoretical astronomer, mathematician, developing the mathematical theory of Laplace by education solar system, calculated that every satellite that happens to be closer than a certain distance to its own central body, than a very specific distance ( Rocha zone), there is an imminent danger of falling apart into its component parts under the influence of the planet’s gravity. This distance is equal to 2.446 radii of the planet, more precisely A = 2.446 Rpl (ρpl /ρ) 1/3. Similar calculations in Russia were made by S.V. Kovalevskaya. The moon is much further away and is not in danger of collapse. (376000/6400≈59R pl).
Possible Moon formation options:
1. The newly formed Earth rotated so quickly that it threw off part of the matter, which then became the Moon. This theory was put forward in 1879 by the English astronomer and mathematician George Darwin. But calculations show that in this case tidal forces would bring it back.
2. In 1962, American geophysicist Harold Urey suggested that the Earth captured the already formed Moon. But given the energy ratio, such a theory is difficult to accept.
3. At the initial stage of the formation of the Solar system, several small moons were first captured, and later the modern Moon was formed from them.
4. In the 60s, a Soviet researcher Evgenia Leonidovna Ruskol, developing the ideas of his teacher, mathematics Otto Yulievich Schmidt, put forward the theory of the joint formation of the Earth and the Moon as a double planet from a cloud of preplanetary bodies that once surrounded the Sun.
5. In 2002, a theory arose, which is now accepted as the most plausible. It was put forward by an American astrophysicist Robin Canup. The basic idea is that when the planets we see now were just forming, a celestial body the size of Mars crashed forcefully into the young, almost formed Earth at a glancing angle. The Moon was formed from the knocked-out substance.

Fixing the material(8 min).

1. The problem is solved independently: Angular diameter The Copernicus crater is 40". What is the true size of the crater? (h=α . D /206265" = 384400 . 40/206265 " = 76 km).
2. The problem is solved independently: The sea of ​​crises has a diameter of 400 km. Is it possible to see it from Earth with the naked eye if the resolution of the eye is 2"? (from D=206265". r/α we find α=206265". r/D= 206265. 400/384400≈214.64"≈215"= 3"35" yes, since this angle is greater than the eye's resolution of 2").
3. Draw to scale the profile of a lunar crater with a diameter of 250 km, if the height of the shaft is 5 km (then, with a shaft height of 2 mm, the diameter of the crater will be 100 mm, which is convenient to depict in the drawing).
4. Calculate how much kinetic energy has a body with a mass of 1 kg when meeting the lunar surface, taking the speed of the body equal to the orbital speed of the Earth. (E=m. v 2 /2= 1*29800 2 /2 = 444020000 J≈444MJ).
5. Derive the formula by which Galileo determined the height of the mountains in the terminator. (Drawing, right triangle).
6. Knowing that the mass of the Moon is 1/81.3 of the mass of the Earth, calculate the acceleration due to gravity on the Moon. (because i.e. g=G. (M . t)/R 2 then we find the ratio for the Earth and the Moon, we get g z /g l =(M z. R l 2)/(M l. R z 2) from here g s /g l =(81.3*1738 2)/6371 2 =245578357.2/40589641≈6.05, then g l = g z / 6,05=9,78/ 6,05≈1,62).

Result:
1) What are the main relief forms of the Moon?
2) What are the physical conditions on the surface of the Moon?
3) Grades.